4803-21-8Relevant academic research and scientific papers
Nickel-Catalyzed Asymmetric Hydrogenation of N-Sulfonyl Imines
Li, Bowen,Chen, Jianzhong,Zhang, Zhenfeng,Gridnev, Ilya D.,Zhang, Wanbin
supporting information, p. 7329 - 7334 (2019/05/01)
An efficient nickel-catalyzed asymmetric hydrogenation of N-tBu-sulfonyl imines was developed with excellent yields and enantioselectivities using (R,R)-QuinoxP* as a chiral ligand. The use of a much lower catalyst loading (0.0095 mol %, S/C=10500) represents the highest catalytic activity for the Ni-catalyzed asymmetric hydrogenations reported so far. Mechanistic studies suggest that a coordination equilibrium exists between the nickel salt and its complex, and that excess nickel salt promotes the formation of the active Ni-complex, and therefore improved the efficiency of the hydrogenation. The catalytic cycle was also investigated by calculations to determine the origin of the enantioselectivity. An extensive network of numerous weak attractive interactions was found to exist between the catalyst and substrate in the transition state and may also contribute to the high catalytic activity.
Asymmetric Stepwise Reductive Amination of Sulfonamides, Sulfamates, and a Phosphinamide by Nickel Catalysis
Zhao, Xiaohu,Xu, Haiyan,Huang, Xiaolei,Zhou, Jianrong Steve
supporting information, p. 292 - 296 (2018/12/13)
Asymmetric reductive amination of poorly nucleophilic sulfonamides was realized in the presence of nickel catalysts and titanium alkoxide. A wide range of ketones, including enolizable ketones and some biaryl ones, were converted into sulfonamides in excellent enantiomeric excess. The cyclization of sulfamates and intermolecular reductive amination of a diarylphosphinamide were also successful. Formic acid was used as a safe and economic surrogate of high-pressure hydrogen gas.
Enantioselective synthesis of cyclic sulfamidates via Pd-catalyzed hydrogenation
Wang, You-Qing,Yu, Chang-Bin,Wang, Da-Wei,Wang, Xiao-Bing,Zhou, Yong-Gui
supporting information; experimental part, p. 2071 - 2074 (2009/04/18)
Using Pd(CF3;CO2)2/(S,S)-f-binaphane as the catalyst, an efficient enantioselective synthesis of cyclic sulfamidates was developed via asymmetric hydrogenation of the corresponding cyclic imines in 2,2,2-trifluoroethanol at room temperature with high enantioselectivities (up to 99% ee).
